The present invention concerns a system of one or more implant devices and excitation device, an implant device and a method using the system and one or more devices for the treatment of arterial and venous structures.
The present invention also concerns implant devices, a system of implant devices and external excitation means, and a method for positioning one or more implant devices in a vessel, and subsequently heating these implant devices, preferably simultaneously, thereby transferring heat from implant devices to the vessel's inner wall.
The general concept of the present invention is to implant one or more implant devices into vessels, said implant devices making contact with the vessels' inner walls at the positions where ablation is deemed necessary. In contrast with prior art, ablation is not performed immediately, but the one or more implant devices can be heated up to a specified temperature by external energy-providing means, which are spatially separated from, i.e. not touching, the implant device and able to provide energy remotely to the implant device for increasing the temperature of the ablation region of the implant device up to an ablation temperature. In a preferred embodiment, an implant device comprises an area which is made from a material which may show magnetic hysteresis and the external energy-providing means are able to create a time-varying magnetic field at the position of the implanted device, hereby heating the implant through the phenomenon of magnetic hysteresis. The maximum temperature the implant device can reach, is limited by the Curie or Néel temperature of the magnetic material used, above which temperature the magnetic hysteresis effect disappears. This Curie or Néel temperature can be engineered precisely to the necessary ablation temperature e.g. by changing the composition of the magnetic alloy that is used. In another embodiment, non-magnetic material may be used, and insulation material may then be used to provide sufficient temperature-controlling means. In an embodiment, the heating of the implant device is done by Joule heating or direct heating, or any other heating system.
The implant device according to the present invention can thus be used in arterial and venous structures.
Indeed, the system, device and method according to the present invention can also be used to perform ablation throughout the renal arteries, to perform ablation of the nervous system surrounding the renal arteries, to perform ablation of the renal sympathetic nerves, more specific to perform ablation of the renal sympathetic nerves in the adventitia surrounding the renal arteries, to perform ablation of renal afferent and/or efferent nerves.
The device can be used in the renal arteries in which case the device, system and method can be used to treat arterial hypertension, norepinephrine spillover, heart failure, hypertension related target organ damage, etc.
The device can be used in the renal arteries in which case the device, system and method can be used to treat arterial hypertension, more specific, but not limited to, mild, moderate and/or severe hypertension, masked hypertension, white-coat hypertension, reverse dipping hypertension, non-dipping hypertension, dipping hypertension end neuroadrenergic hypertension.
The devices, systems and methods as described in this document may also be used in human or animal corpses or in models of human or animal bodies, e.g. for practicing or educational purposes, whereby the heating of the implant devices leaves ablation marks on the vessel's inner wall which can be used to check if the implant devices were positioned correctly and sufficient ablation occurred.
The present document focuses its description on the application of the device inside the renal arteries.
A person skilled in the art will be able to interpret the device, the system and the method and to provide them of specific features, components or steps if to be used in other areas.
Human wellbeing is menaced by numerous disorders which change with time. The art of medicine continuously needs to innovate and to adapt to these changes.
US patent application 2005/0027306 discloses a catheterization device for delivering a self-expanding stent. The device has an inner shaft and an outer shaft moveable with respect to the inner shaft. The self-expanding stent is received on the inner shaft adjacent its distal end. A tapered tip is located on the inner shaft distal end and it forms a smooth transition from the delivery device to a guidewire extending therethrough. A handle allows a practitioner to deploy the stent single handedly. The stent may have its segments in a first radial configuration for delivery of the stent or the stent may have a plurality of segments in a first radial configuration and a plurality of second segments in a second radial position.
US patent application 2005/0101946 discloses a method and system for treating AF by ablation of a pulmonary vein, using a stent which has a resonant circuit. The stent can be implanted at the site of ablation and subsequently activated by external energy-providing means, in particular by an electromagnetic field with the resonating frequency of the resonant circuit of the stent. The application does not disclose the possibility of using materials which show magnetic hysteresis for at least part of the stent, and to use the hysteresis effect for activating the stent. Thereby, it is also in this way not easy to control the ablation temperature of the stent. The energy delivered to the stent should be monitored very closely as it depends on a multitude of factors and the temperature of the stent is not under control, such as the electrical resistance of the stent and the resonant circuit of the stent, the magnitude of the RF field at the site of the stent, the quality of the thermal contact between stent and vessel wall.
European patent application EP 1 036 574 discloses a device and method for heating an implanted stent up to a certain temperature, using external energy-providing means. The stent can be heated up through the effect of magnetic hysteresis. However, in this patent application, the temperature is controlled by an external controlling system which measures the temperature of the stent via e.g. an infrared camera, and alters the energy provided with the external energy-providing means accordingly. Hereby, it is not explicitly disclosed that the system is used for ablation. Furthermore, the temperature is controlled by an external feedback system, and not e.g. by the material properties of the stent. Moreover, European patent application EP 1 036 574 does not disclose that the stent or implant may subtend at least a substantially complete circumferential band of the vessel's inner wall.
U.S. Pat. No. 7,235,096 discloses an implantable stent for treating a damaged body lumen, which comprises tubular stent body having several interconnected microholes distributed throughout the body uniformally along the entire length of the body. The tubular stent body has several interconnected microholes distributed throughout the stent body substantially uniformally along the entire length of the stent body; the several microholes are small so as to promote an organized growth pattern of infiltrating cells throughout the stent body, and the stent body is otherwise substantially free of holes larger than the microholes; the stent body is formed from a fibrous three dimensional non-woven matrix. The patent also discloses a stent system comprising the stent in spaced juxtaposition to an energy source for transcutaneously applying energy to the stent, thereby causing the temperature of the stent to increase to a temperature above body temperature (preferably 38-49° C.). It further discloses an active stent comprising the stent and further comprising live cells growing in the interconnected microholes. A method for measuring flow of a fluid through a body lumen is disclosed, involving: implanting the stent into a body lumen having a flow of fluid through it; energizing the implanted stent transcutaneously to raise its temperature above body temperature; monitoring transcutaneously the output from at least one of the temperature sensors upon cessation of the energizing to determine the cooling rate at each of the at least one sensor: and obtaining the flow rate of the fluid through the stent from the cooling rate at the at least one sensor. Also disclosed is a method for treating a tubular body organ in a subject involving: promoting the ingrowth of living cells in the stent; and implanting the stent into the tubular organ of the subject prior to or following promoting the ingrowth of the living cells so as to treat the tubular organ, whereby the stent body is formed from a fibrous three dimensional non-woven matrix.
In U.S. Pat. No. 7,235,096, the temperature of the stent can be controlled by an at least partially external control system. In this case, the temperature sensor or sensors transmit the measured temperature to said external control system, which then controls the external energy source. Further, in this patent, the temperature of the stent can be controlled by the use of material with a Curie temperature whereby the heating of the stent occurs via hysteresis heating. Hereby the temperature of the stent is limited to the Curie temperature, since the mechanism of hysteresis heating only works below the Curie temperature. Both temperature control mechanisms, i.e. the external control system and the use of magnetic materials, have their shortcomings.
The mechanism comprising the external control system leads to the necessity of a dedicated external energy source, specifically adapted for receiving the temperature from the temperature sensor. Furthermore, in such a system the energy source, which in most cases will be a radiofrequent field, will need to be controlled in intensity and possibly also in frequency in order for the implant to be kept at a desired temperature.
The mechanism of hysteresis heating has a number of difficulties, especially in finding the correct alloy with an optimal Curie temperature. As this optimal temperature may be different case-by-case, a different alloy may need to be found for different temperatures.
There remains a need in the art for improved devices, systems and methods for the ablation of a substantially complete circumferential band or a spiraling band around a vessel's wall from the inside. The present invention aims to resolve at least some of the problems mentioned above, e.g. to make sure that the ablation is performed for a substantially complete circumferential band or a spiraling band around a vessel's wall from the inside, that the ablation itself can be triggered with external means and this multiple times if necessary, that the ablation temperature is well under control and does not depend on less-controlled elements in the treatment or on an intricate monitoring system, etc.
The present invention tries to overcome the problems by providing an implant with a built-in temperature control and/or measuring means, whereby said control means are capable of keeping the temperature of at least part of the implant to or below a desired temperature. The present invention also provides a system and method for heating an implant to or up to a desired maximal temperature.